Passenger&#39;s weight measurement device for vehicle seat

ABSTRACT

A passenger&#39;s weight measurement device for a vehicle seat includes an upper rail provided on a lower rail that is fixable to a vehicle floor, the upper rail being movable in at least one of rear and front directions; a load sensor fixed onto the upper rail; and a frame provided on the load sensor and below the vehicle seat. In plan view, the load sensor protrudes from the frame in at least one of left and right directions.

This is Continuation of U.S. application Ser. No. 14/842,185 filed onSep. 1, 2015, which is a continuation of U.S. application Ser. No.13/836,773 filed Mar. 15, 2013, which is a Continuation of U.S.application Ser. No. 13/137,713 filed Sep. 7, 2011, which is aContinuation of U.S. application Ser. No. 12/875,594 filed Sep. 3, 2010,which is a Continuation of U.S. application Ser. No. 11/992,548 filedMar. 25, 2008, which is a National Stage of International ApplicationNo. PCT/JP2006/319477 filed Sep. 29, 2006, which in turn claims thebenefit of priority from Japanese Application No. 2005-286881 filed Sep.30, 2005. The disclosures of the prior applications are herebyincorporated by reference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a passenger's weight measurement devicefor a vehicle seat, which measures a weight of a passenger seated on thevehicle seat, and to an attachment structure for attaching a load sensorto the passenger's weight measurement device.

BACKGROUND ART

In recent years, in some cases, operations of various safety devicessuch as a seat belt and an air bag have been controlled in accordancewith a weight of a passenger seated on a vehicle seat for the purpose ofenhancing performance of the safety devices. In a conventionalpassenger's weight measurement device that measures the weight of theseated passenger, a load sensor is interposed between a vehicle floorand the vehicle seat (for example, refer to Patent Document 1 and PatentDocument 2).

Patent Document 1: JP A H8-164039 Patent Document 2: JP A H9-207638DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, there is a dimension error or an assembling position error whenthe passenger's weight measurement device is assembled, when the vehicleseat is fixed to the passenger's weight measurement device or when thepassenger's weight measurement device is fixed to the vehicle floor, orthe like. Accordingly, it has been difficult to assemble the passenger'sweight measurement device.

In this connection, it is an object of the present invention to providea passenger's weight measurement device for a vehicle seat, which ismore easily assembled, and to provide an attachment structure for a loadsensor.

Means for Solving the Problems

In order to solve the above-described problem, a passenger's weightmeasurement device for a vehicle seat according to the present inventioncomprises: an upper rail provided on a lower rail fixed to a vehiclefloor so as to be movable in a rear and front direction; a load sensorfixed onto the upper rail; and a frame provided on the load sensor andbelow the vehicle seat, wherein a rod is extended from the load sensor,the rod sequentially penetrates the frame and a spring holder and isinserted into a coil spring, a nut is screwed to the rod from above thespring holder, and the coil spring is sandwiched between the springholder and the frame and is compressed by tightening the nut to thespring holder.

An attachment structure for a load sensor according to the presentinvention is an attachment structure for attaching the load sensor to aframe provided below a vehicle seat, wherein a rod is extended from theload sensor, the rod sequentially penetrates the frame and a springholder and is inserted into a coil spring, a nut is screwed to the rodfrom above the spring holder, and the coil spring is sandwiched betweenthe spring holder and the frame and is compressed by tightening the nutto the spring holder.

In the present invention, preferably, the spring holder includes a cupportion in which a through hole through which the rod penetrates isformed in a bottom, and a flange formed on an outer circumference of thecup portion, and the cup portion is inserted through the coil spring,the nut is inserted into the cup portion to tighten the bottom of thecup portion, and the coil spring is sandwiched between the flange andthe flame.

In the present invention, preferably, a collar through which the rod isinserted penetrates the frame, the spring holder is sandwiched betweenthe collar and the nut, and the coil spring and the collar aresandwiched between the nut and the load sensor.

In accordance with the present invention, the nut is screwed to the rodfrom above the spring holder, and the coil spring is sandwiched betweenthe spring holder and the frame by tightening the nut. Accordingly, theframe can be shifted in the vertical direction with respect to the loadsensor.

Effect of the Invention

In accordance with the present invention, the frame can be shifted inthe vertical direction with respect to the load sensor. Accordingly,even if the lower rail, the upper rail, the frame and the like aredistorted during the assembling or the like, an initial load generatedby such distortions can be prevented from being applied to the loadsensor.

Moreover, the coil spring is sandwiched between the frame and the springholder in a state of being compressed by tightening the nut.Accordingly, the load sensor is fixed to the frame more stably andappropriately. Therefore, it becomes easier to assemble the passenger'sweight measurement device.

Furthermore, the load is stably applied from the coil spring to the nutowing to elastic deformation of the coil spring, which is caused bytightening the nut.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 This is a perspective diagram of a passenger's weight measurementdevice 1 for a vehicle seat.

FIG. 2 This is an exploded perspective diagram of the passenger's weightmeasurement device 1.

FIG. 3 This is a perspective diagram of a load sensor 21.

FIG. 4 This is a plan diagram of a rectangular frame 30.

FIG. 5 This is a plan diagram of a right front portion of therectangular frame 30.

FIG. 6 This is a cross-sectional diagram showing a cross section along asection line VI-VI of FIG. 5.

FIG. 7 This is a cross-sectional diagram showing a cross section along asection line VII-VII of FIG. 5.

FIG. 8 This is a cross-sectional diagram showing a modification exampleof FIG. 6, and showing a cross section along the section line VI-VI in asimilar way to FIG. 6.

FIG. 9 This is a cross-sectional diagram showing a modification exampleof FIG. 7, and showing a cross section along the section line VII-VII ina similar way to FIG. 7.

BEST MODE FOR CARRYING OUT THE INVENTION

A best mode for carrying out the present invention will be describedbelow by using the drawings. On embodiments to be described below, avariety of technically preferable limitations are imposed in order tocarry out the present invention; however, the scope of the invention isnot limited to the following embodiments and illustrated examples.

FIG. 1 is a perspective diagram of a passenger's weight measurementdevice 1 for a vehicle seat, and FIG. 2 is an exploded perspectivediagram of the passenger's weight measurement device 1.

As shown in FIG. 1 and FIG. 2, a slide adjuster 2 for adjusting aback-and-forth position of the vehicle seat is attached onto a floor ofa passenger's room. The slide adjuster 2 includes a left and right pairof lower rails 3 provided in parallel to each other, a left and rightpair of upper rails 4 engaged with the lower rails 3 so as to be capableof sliding on the respective lower rails 3 in a rear and front directionwith respect to the lower rails 3, a lower bracket 5 fixed to lowersurfaces of the lower rails 3 by bolt/nut coupling or rivet coupling andbridged between the left and right lower rails 3, a lock mechanism 6 forlocking the upper rails 4 to the lower rails 3 and for releasing thelocking, brackets 7 attached onto front end portions of the lowersurfaces of the respective lower rails 3, and brackets 8 attached ontorear end portions of the lower surfaces of the respective lower rails 3.These brackets 7 and 8 are attached onto the vehicle floor, and thelower rails 3 are fixed to the vehicle floor.

Brackets 9 are fixed to middle positions of upper surfaces of therespective upper rails 4 in a rear and front direction by the bolt/nutcoupling or the rivet coupling. The brackets 9 are provided in a stateof being erected with respect to upper surfaces of the upper rails 4. Aright end portion of a submarine pipe 10 is welded to the brackets 9,and the submarine pipe 10 is bridged between the two left and rightbrackets 9.

A load sensor 21 is mounted on a front end portion of the upper surfaceof the right upper rail 4, and another load sensor 21 is mounted on arear end portion thereof. Also on the upper surface of the left upperrail 4, load sensors 21 are mounted on a front end portion and rear endportion thereof, respectively. When viewed from the above, these fourload sensors 21 are arranged so as to be apexes of a square or arectangle.

FIG. 3 is a perspective diagram of the load sensor 21. All of the loadsensors 21 are provided in a similar way. As shown in FIG. 3, the loadsensor 21 includes a columnar sensing portion 21 a that senses a load, aplate-like flange portion 21 b extending horizontally in a rear andfront direction from a lower end of the sensing portion 21 a, a rod 21 cextending upward from an upper end of the sensing portion 21 a, and aconnector 21 d extending from the sensing portion 21 a so as to beparallel to the flange portion 21 b. The rod 21 c is formed into a malescrew shape. Female screw-shaped circular holes 21 e and 21 f whichpenetrate the flange portion 21 b in the vertical direction are formedin front and rear portions of the flange portion 21 b, respectively. Thesensing portion 21 a incorporates a strain gauge therein, and the loadis converted into an electric signal by the strain gauge.

As shown in FIG. 2, the load sensor 21 is fixed to the right upper rail4. Specifically, a lower surface of the flange portion 21 b abuts on theupper surface of the upper rail 4, and two bolts 22 inserted through theupper rail 4 upward from below are screwed to the circular holes 21 eand 21 f, respectively. Therefore, the load sensor 21 is fixed. Notethat the load sensor 21 may be fixed to the upper rail 4 by fasteningnuts to the bolts 22 on the flange portion 21 b without forming anyscrew threads in the circular holes 21 e and 21 f.

Any load sensor 21 is fixed to the upper rails 4 as described above.However, with regard to the two load sensors 21 fixed to the rearportions thereof, the connectors 21 d are directed forward, and withregard to the two load sensors 21 fixed to the front portions thereof,the connectors 21 d are directed backward.

As shown in FIG. 1 and FIG. 2, the frame 30 having a rectangular frameshape is mounted on these four load sensors 21. FIG. 4 is a top diagramof the rectangular frame 30. As shown in FIG. 4, the rectangular frame30 is composed of a left and right pair of beams 31, a front beam 32,and a rear cross pipe 33.

Either of the beams 31 is a metal member having a U-shaped crosssection, and has a web 31 a, an inner flange 31 b, and an outer flange31 c. Attachment holes 31 d are formed in a front portion and a rearportion of the web 31 a, respectively.

The front beam 32 is a metal member having a U-shaped cross section, andhas a web 32 a, a front flange 32 b, and a rear flange 32 c. The frontbeam 32 is bridged between front end portions of the left and rightbeams 31, and is welded to these beams 31.

The cross pipe 33 is bridged between rear end portions of the left andright beams 31, and is welded to these beams 31.

The rods 21 c of the load sensors 21 are inserted into the respectiveattachment holes 21 d upward from below, and nuts 46 are screwed to therods 21 c. Therefore, the load sensors 21 are attached onto a rightfront portion, a right rear portion, a left front portion and a leftrear portion of the rectangular frame 30, respectively. Referring toFIG. 5 to FIG. 7, an attachment structure for attaching the right frontload sensor 21 onto the right front portion of the rectangular frame 30will be described. FIG. 5 is a plan diagram of the right front portionof the rectangular frame 30, FIG. 6 is a cross-sectional diagram showinga cross section along a line VI-VI, and FIG. 7 is a cross-sectionaldiagram showing a cross section along a line VII-VII. As shown in FIG. 5to FIG. 7, an annular bush 41 is fitted to an edge of the right frontattachment hole 31 d, and grease is applied on the bush 41. The bush 41is an oilless bush formed by impregnating oil into a metal material, oris made of synthetic resin. The bush 41 may be one made of othermaterials. Moreover, a stepped collar 42 composed of a cylindricalportion 42 a and an annular plate-like flange portion 42 b formed on oneend surface of the cylindrical portion 42 a is inserted through theattachment hole 31 d in an inside of the bush 41. Here, the cylindricalportion 42 a is inserted through the attachment hole 31 d upward frombelow, and the flange portion 42 b engages with a lower surface of theweb 31 a via the bush 41. Therefore, the stepped collar 42 is not pulledout upward. Moreover, the cylindrical portion 42 a protrudes from anupper surface of the web 31 a, and an upper end surface of thecylindrical portion 42 a is located at a higher position than the uppersurface of the web 31 a. Here, the cylindrical portion 42 a is fitted tothe bush 41, and there is no gap between the cylindrical portion 42 aand the bush 41.

The rod 21 c of the load sensor 21 is inserted through the steppedcollar 42 upward from below. An inner diameter of the stepped collar 42is designed to be slightly larger than a diameter of the rod 21 c, andby such designing, a dimension error and an attachment position errorare solved.

The nut 46 is screwed to the rod 21 c. A plain washer 43, a coil spring44 and a spring holder 45 are interposed between the upper surface ofthe web 31 a of the beam 31 and the nut 46. The rod 21 c and thecylindrical portion 42 a of the stepped collar 42 are inserted throughthe plain washer 43, and the plain washer 43 is set in a state of beingmounted on the web 31 a, and particularly, on the bush 41. Furthermore,the rod 21 c is inserted through the coil spring 44, and the coil spring44 is set in a state of being mounted on the plain washer 43. A portionof the coil spring 44, which is brought into contact with the plainwasher 43, is formed to be flat.

The spring holder 45 includes a cup portion 45 c in which a through holeis formed in a bottom 45 b, and an annular flange 45 a formed on anouter circumferential surface in an opening of the cup portion 45 c.Then, the rod 21 c penetrates through the through hole of the bottom 45b of the cup portion 45 c, the bottom 45 b of the cup portion 45 c isset in a state of being mounted on an end surface of the stepped collar42, and the cup portion 45 c is inserted into the coil spring 44.Moreover, the coil spring 44 and the plain washer 43 are set in a stateof being sandwiched between the flange 45 a of the spring holder 45 andthe web 31 a.

The nut 46 is screwed to the rod 21 c in a state of being inserted intothe cup portion 45 c, and by tightening the nut 46, the bottom 45 b ofthe cup portion 45 c is sandwiched between the nut 46 and the upper endsurface of the cylindrical portion 42 a, and the coil spring 44 and theplain washer 43 are sandwiched between the flange 45 a and the web 31 aof the beam 31. Moreover, since the coil spring 44 is compressed bytightening the nut 46, the load is applied to the nut 46, andaccordingly, the nut 46 is prevented from being loosened. Note that thecoil spring 44 is set in a state of being mounted on the web 31 a of thebeam 31 via the plain washer 43. However, the coil spring 44 may be setin a state of being directly mounted on the web 31 a of the beam 31, andthe coil spring 44 may be sandwiched between the flange 45 a and the web31 a.

Like the right front load sensor 21, the left front, left rear and rightrear load sensors 21 are attached onto the left front, left rear andright rear attachment holes 31 d, respectively. In a state where thefour load sensors 21 are attached onto the rectangular frame 30, thesubmarine pipe 10 is located behind the front beam 32.

As shown in FIG. 1 and FIG. 2, side frames 51 are welded to the outerflanges 31 c of the left and right beams 31, respectively. These sideframes 51 are parts of a bottom frame of the vehicle seat.

From above, front portions of the side frames 51 are covered with a panframe 53, and the side frames 51 and the pan frame 53 are fixed to eachother by the bolt/nut coupling or the rivet coupling. A seat spring 54is bridged between the cross pipe 33 and the pan frame 53, a cushion ismounted on the pan frame 53 and the seat spring 54, and the cushion, thepan frame 53 and the side frames 51 are entirely covered with a cover.

A backrest frame is coupled to rear ends of the side frames 51, and iscapable of rising and falling by a reclining mechanism. Note that thebackrest frame and the cushion are not shown in order to make it easy toview the drawings.

In the passenger's weight measurement device 1 configured as describedabove, when a passenger is seated on a seat bottom, a weight of thepassenger is applied to the four load sensors 21 through the rectangularframe 30, and is converted into electric signals by these load sensors21.

Here, the load sensors 21 are attached between the upper rails 4 and therectangular frame 30, and the load sensors 21 move in a rear and frontdirection integrally with the vehicle seat. Accordingly, a load inputtedfrom the vehicle seat to the load sensors 21 can be always kept constantirrespective of position of the vehicle seat in a rear and frontdirection. Therefore, measuring accuracy of the passenger's weight canbe enhanced.

Moreover, the spring holder 45 is mounted on the upper end surface ofthe stepped collar 42, and the coil spring 44 is sandwiched between thespring holder 45 and the web 31 a by tightening the nut 46. Accordingly,the rectangular frame 30 can be shifted in the vertical direction withrespect to the load sensors 21. Therefore, noise of the load generatedby distortion of the slide adjuster 2 and the like becomes smaller.

Moreover, even if the rectangular frame 30 can be shifted in thevertical direction with respect to the load sensors 21, the coil springs44 are interposed between the nuts 46 and the webs 31 a, andaccordingly, the load sensors 21 can be fixed to the rectangular frame30 more stably and appropriately. Therefore, it becomes easier toassemble the passenger's weight measurement device 1.

Moreover, the load is stably applied from each of the coil springs 44 toeach of the nuts 46 owing to elastic deformation of the coil spring 44,which is caused by tightening the nut 46.

Moreover, the submarine pipe 10 is located behind the front beam 32, andaccordingly, when forward inertial force is applied to the passengerowing to a frontal collision or the like of the vehicle, buttocks of thepassenger seated on the vehicle seat are restrained by the submarinepipe 10. Therefore, a so-called submarine phenomenon in which thepassenger moves under a waist belt can be prevented.

Note that the present invention is not limited to the above-describedembodiment, and various improvements and design changes can be madewithin the scope without departing from the gist of the presentinvention.

In the above-described embodiment, the coil spring 44 is set in thestate of being mounted on the plain washer 43, and the portion of thecoil spring 44, which is brought into contact with the plain washer 43,is made flat. However, for example as shown in FIG. 8 and FIG. 9, awasher 431 in which an inner portion thereof is formed as a protrudingportion 431 a protruding upward, may be used. An outer edge portion ofthe protruding portion 431 a is formed into a curved surface, and a stepdifference 431 b formed by the protruding portion 431 a is formed on anupper surface of the washer 431. An end portion of the coil spring 44 isset in a state of being engaged with the step difference 431 b, and thecoil spring 44 abuts on the curved surface of the protruding portion 431a and a flat surface of the washer 431. Therefore, the coil spring 44 iscentered by the protruding portion 431 a of the washer 431 so as not toslip on the flat surface of the washer 431.

What is claimed is:
 1. A passenger's weight measurement device for avehicle seat, comprising: an upper rail provided on a lower rail that isfixable to a vehicle floor, the upper rail being movable in at least oneof rear and front directions; a load sensor fixed onto the upper rail;and a frame provided on the load sensor and below the vehicle seat,wherein in plan view, the load sensor protrudes from the frame in atleast one of left and right directions.
 2. The passenger's weightmeasurement device according to claim 1, wherein flanges that extend inat least one of the rear and front directions are formed along edges ofthe frame.
 3. The passenger's weight measurement device according toclaim 1, wherein the frame has a wider portion at the load sensor, thewider portion being wider than other portions of the frame.
 4. Thepassenger's weight measurement device according to claim 3, wherein theload sensor is fixed to the frame by a nut at the wider portion of theframe.
 5. The passenger's weight measurement device according to claim3, wherein in plan view, the load sensor protrudes from the widerportion of the frame in at least one of the rear and front directions.6. The passenger's weight measurement device according to claim 3,wherein a flange is formed along an edge of the wider portion of theframe.
 7. The passenger's weight measurement device according to claim1, wherein the load sensor includes: a sensing portion that senses aload; a flange portion that extends in at least one of the rear andfront directions from a lower end of the sensing portion; and a rod thatextends upward from an upper end of the sensing portion to be fixed tothe frame, wherein holes that penetrate the flange portion in thevertical direction are formed in front and rear portions of the flangeportion, and wherein the load sensor is fixed to the upper rail by wayof the holes.
 8. The passenger's weight measurement device according toclaim 7, wherein the load sensor includes a connector that extends fromthe sensing portion so as to be parallel to the flange portion, andwherein a horizontal distance between the rod and an end of theconnector is longer than a horizontal distance between the rod and asaid hole of the flange portion.